<template>
  <div id="root">
    <div class="todo-container">
      <div class="todo-wrap">
        <MyHeader @add="add"/>
        <MyList :todos="todos"/>
        <MyFooter :todos="todos" @isAllTodo="isAllTodo" @clearAllTodo="clearAllTodo"/>
      </div>
    </div>
  </div>
</template>

<script>

  // 创建App组件
  import pubsub from "pubsub-js";
  import MyHeader from "@/components/MyHeader";
  import MyFooter from "@/components/MyFooter";
  import MyList from "@/components/MyList";
  export default {
    name:'App',
    components:{
      MyHeader,
      MyFooter,
      MyList
    },
    data(){
      return{
        // 如果为null，就用空数组
        todos:JSON.parse(localStorage.getItem('todos')) || []
      }
    },
    methods:{
      // 添加一个todo
      add(todo){
        this.todos.unshift(todo)
      },
      // 勾选or取消勾选一个todo
      checkTodo(id){
        this.todos.forEach((todo)=>{
          if(todo.id === id){
            todo.done = !todo.done
          }
        })
      },
      // 删除一个todo
      deleteTodo(_,id){
        this.todos = this.todos.filter(todo => todo.id !== id)
      },
      // 全选或取消全选
      isAllTodo(value){
        this.todos.forEach((todo) => todo.done = value)
      },
      // 清除已完成
      clearAllTodo(){
        this.todos = this.todos.filter((todo)=>{
          return !todo.done
        })
      }
    },
    watch:{
      todos:{
        // 开启深度监视
        deep:true,
        handler(value){
          localStorage.setItem('todos',JSON.stringify(value))
        }
      }
    },
    mounted() {
      this.$bus.$on('checkTodo',this.checkTodo)
      // this.$bus.$on('deleteTodo',this.deleteTodo)
      pubsub.subscribe('deleteTodo',this.deleteTodo)
    },
    beforeDestroy() {
      this.$bus.$off('checkTodo')
      // this.$bus.$off('deleteTodo')
    }
  }
</script>

<style>
/*base*/
body {
  background: #fff;
}

.btn {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 0;
  font-size: 14px;
  line-height: 20px;
  text-align: center;
  vertical-align: middle;
  cursor: pointer;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2), 0 1px 2px rgba(0, 0, 0, 0.05);
  border-radius: 4px;
}

.btn-danger {
  color: #fff;
  background-color: #da4f49;
  border: 1px solid #bd362f;
}

.btn-danger:hover {
  color: #fff;
  background-color: #bd362f;
}

.btn:focus {
  outline: none;
}

.todo-container {
  width: 600px;
  margin: 0 auto;
}

.todo-container .todo-wrap {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}

</style>